diff --git a/xCAT-server/lib/perl/xCAT/PPC.pm b/xCAT-server/lib/perl/xCAT/PPC.pm
old mode 100644
new mode 100755
index a833ac540..0f4f35334
--- a/xCAT-server/lib/perl/xCAT/PPC.pm
+++ b/xCAT-server/lib/perl/xCAT/PPC.pm
@@ -1007,13 +1007,18 @@ sub resolve_netwk {
         }
         my $gateway = $nethash{$_}{gateway};
         my $gateway_ip;
-        if ( defined( $gateway )) {
+        if ( defined( $gateway ) && $gateway) {
             $ip = xCAT::NetworkUtils::toIP( $gateway );
             if ( @$ip[0] != 0 ) {
                 send_msg( $request, 1, "$_: Cannot resolve '$gateway'" );
                 next;  
             }
             $gateway_ip = @$ip[1];
+        } else {
+            # If the <xcatmaster> is the gateway, the ip forwarding must be enabled on the MN/SN,
+            # xCAT will setup the ipforarding automatically, but still see problems about the ip forwarding occassionally.
+            send_msg( $request, 1, "$_: No gateway defined for this node, check the networks table. If the gateway in the networks table is '<xcatmaster>', check the ip forwarding setup on the management node and service nodes.");
+            next;
         }
 
         my $netmask = $nethash{$_}{mask};